Two species of Rhabdoweisia B.S.G. are recognised for southern Africa: R. crispata (Dicks.) Lindb. is reported new to Africa and the distribution of R. fugax (Hedw.) B.S.G. is extended to include the eastern Transvaal. Original material of Bryum crispatum Dicks. in the Dickson Herbarium (BM) is selected as lectotype for the species. Illustrations, a distribution map, and a key to the species are provided. Rhabdoweisia B.S.G. is typified by R. fugax (Hedw.) B.S.G. and the generic name refers to the ribbed capsule and a supposed resemblance to Weissia Hedw. Lawton (1961) recognised four species in a revision of the genus. The genus is known from Europe, Greenland, North America, South America, Asia, Africa, and several islands. Rhabdoweisia is characterised by: a) small plants; b) ligulate to linear-lanceolate leaves; c) rounded-quadrate or rounded-hexagonal essentially smooth laminal cells; d) rectangular thin-walled frequently hyaline basal laminal cells; e) median guide cells of the costa; f) erect 8-ribbed ovoid capsules; g) single peristome with 16 narrow teeth; h) phaneropore stomata; and i) cucullate naked calyptrae. Rhabdoweisia fugax was reported from southern Africa by Sim (1926) and Magill and Schelpe (1979). Rhabdoweisia was treated in the family Rhabdoweisiaceae by Magill and Schelpe (1979) but most authors, including Sim (1926), placed the genus in the Dicranaceae. As a result of a recent revision for the Flora ofSouthern Africa, two species ofRhabdoweisia are recognised for the region. The following key and illustrations are based on southern African material in PRE. KEY TO THE SPECIES OF RHABDOWEISIA IN SOUTHERN AFRICA Leaf margins entire to crenulate, apex generally acuminate, cells in (4-)5-7(-8) rows on each side of costa at leaf middle; spores 11-17 gm ....... 1. R. FUGAX Leaf margins irregularly denticulate, apex generally acute, cells in (5-)7-9(-10) rows on each side of costa at leaf middle; spores 16-25m 2. R. CRISPATA 1. RHABDOWEISIA FUGAX (Hedw.) B.S.G., Bryol. Eur. 1: 98. 1846. (FIG. 1-13) Weisia fugax Hedw., Spec. Musc. 64. 1801. TYPE: Germany, Sudeten, Breutel, Musci frondosi 260 (NY, neotype) fide Lawton in THE BRYOLOGIST 64: 144. 1961. The species is recognised by the linear-lanceolate leaves with acuminate apices, entire to crenulate leaf margins, and the single peristome with distant filiform teeth, abruptly narrowed from a low basal membrane. Phytogeography-ecology. -Rhabdoweisia fugax is known from Europe, the Faroes, Madeira, Azores, South and Central America, and southern Africa. The species is rare in southern Africa and was last collected in 1911. It occurs in the Drakensberg Mountains at Van Reenen in Natal and near Pilgrim's Rest in the eastern Transvaal (Fig. 27). This is the first report of the species from the eastern Transvaal. Both localities are included in the Grassland Biome (Rutherford & Westfall 1986) at altitudes of approximately 1,700 and 1,500 m, respectively. Specimens examined. -South Africa. Natal: Van Reenen, Wager PRE-CH535. Transvaal: in mont Kwathlamba supra Pilgrim's Rest, MacLea sub Rehmann 501. 2. RHABDOWEISIA CRISPATA (Dicks.) Lindb., Act. Soc. Sci. Fenn. 10: 22. 1871. (FIG. 14-25) Bryum crispatum Dicks., plantarum cryptogamicarum Britanniae 4: 29. 1801. TYPE: Specimen number 30 on sheet 32 in the herbarium of James Dickson (BM, lectotype, selected here). This species is most easily separated from R. fugax by the shape of the peristome teeth. The filiform teeth of R. fugax abruptly narrow from the basal membrane while the narrowly lanceolate teeth of R. crispata taper evenly from the broad base. Although mature peristomes were not found in the southern African specimen, the species can be distinguished from the closely related R. fugax by the broader leaves, mostly acute leaf apices, irregularly denticulate leaf margins, and larger spores. In the index to plantarum cryptogamicarum Britanniae, Dickson (1801) referred to his earlier de0007-2745/91/409-412$0.55/0 This content downloaded from 157.55.39.102 on Sat, 24 Dec 2016 05:19:33 UTC All use subject to http://about.jstor.org/terms